Ferrofluid is one of the most beautiful, and messy, substances in the world. Ferrofluid derives from Latin and means "ferrum", iron, "fluid", fluid. It's a magnetic substance that forms shapes when close to a magnetic field. When away from a magnetic field, it appears to be any other liquid, it has about the same consistency as water but is black and shiny, but the real magic begins when it is in a magnetic field. Ferrofluid was actually discovered in the mid 1960's by NASA scientists as a way of controlling liquids in space. The benefits of it being magnetic were obvious, the fluid could be easily manipulated and made to flow different directions at different forces. Ferrofluids actually contain tiny (~10 nm diameter) magnetic particles in a liquid suspension. When the particles are affected by a magnetic field, they line up in relation to the field and next to the most focused parts of the magnets (the poles) it create forms spikes. If the magnet is not strong enough it will only create a bulge in the liquid, meaning all it is doing is pulling it towards it. Our experiment is to test if the amount of fluid and number (strength) of magnets, would directly affect the height generated by the ferrofluid.
Ferrofluid over magnet creating a spike pattern.
WARNING: If attempting to recreate this experiment, know that it is very hard to get off clothes and skin and we highly recommend you use goggles, gloves and a lab coat. Thank you and have fun!
Procedure
This procedure was relatively simple due to our access to pre-made ferrofluid, if you do not have access to said compound there are tutorials for making your own or you can buy it. First we poured 20 ml of ferrofluid into a Petri dish making sure not to spill. We then attached a single neodymium magnet (1/2cm thick and 2cm in diameter), putting the flat end to the bottom of the dish, and used a very thin copper wire to measure the height (using the stain in the wire to measure with a ruler). Next, we turned the magnet on its side and again measured the height. After that, we added another magnet and repeated the previous process. We did this until we had four magnets on the bottom. After we finished that, we added 10 ml of ferrofluid to the dish, repeating all the processes with magnets. After we finished that we added another 10 ml to the dish and again repeated all the magnet tests.
Results
For the graphs below we are comparing the amount of fluid to the height and the number of magnets to the height. In both graphs, blue triangles are tests when the magnets were upright and red diamonds are when the magnets were sideways.
Amount of fluid in relation to the height of the fluid.
Number of magnets in relation to height.
Sideways
Magnets
Fluid (ml)
Height
(cm)
1
1
2
.7
2
1
3
.6
3
1
4
.8
4
2
2
.7
5
2
3
.9
6
2
4
1.1
7
3
2
.6
8
3
3
.6
9
3
4
1
10
4
2
.5
11
4
3
.5
12
4
4
.8
Upright
Magnets
Fluid (ml)
Height (cm)
1
1
2
.9
2
1
3
1.1
3
1
4
1.4
4
2
2
1
5
2
3
1.1
6
2
4
1.4
7
3
2
.9
8
3
3
1.1
9
3
4
1.4
10
4
2
.9
11
4
3
1.2
12
4
4
1.5
Conclusions
For upright magnets, we found that adding magnets to the bottom of the dish did not affect the height of the ferrofluid. Though it comes as no surprise that four magnets made the highest tower, the thing that really affected the height was the amount of fluid. With four magnets and 4 ml of ferrofluid, we got a height of 1.5 cm. However with sideways magnets, the more magnets the shorter the fluid was. We found that using 2 magnets and 4 ml of fluid we got the highest result of 1.1 cm. More than 2 magnets causes the fluid to be stretched out and not go out as far. One magnet was not able to support all the fluid in the dish so it could not lift it up as far as two, even though it's more efficient. So if you ever play with ferrofluid, we recommend you use 4+ ml of fluid and 4+ magnets stacked on top of each other in a tower. If we were to extend this experiment, we would definitely add more fluid and more magnets to the conditions.
Ferrofluid and Magnets
Table of Contents
Introduction
Ferrofluid is one of the most beautiful, and messy, substances in the world. Ferrofluid derives from Latin and means "ferrum", iron, "fluid", fluid. It's a magnetic substance that forms shapes when close to a magnetic field. When away from a magnetic field, it appears to be any other liquid, it has about the same consistency as water but is black and shiny, but the real magic begins when it is in a magnetic field. Ferrofluid was actually discovered in the mid 1960's by NASA scientists as a way of controlling liquids in space. The benefits of it being magnetic were obvious, the fluid could be easily manipulated and made to flow different directions at different forces. Ferrofluids actually contain tiny (~10 nm diameter) magnetic particles in a liquid suspension. When the particles are affected by a magnetic field, they line up in relation to the field and next to the most focused parts of the magnets (the poles) it create forms spikes. If the magnet is not strong enough it will only create a bulge in the liquid, meaning all it is doing is pulling it towards it. Our experiment is to test if the amount of fluid and number (strength) of magnets, would directly affect the height generated by the ferrofluid.
WARNING: If attempting to recreate this experiment, know that it is very hard to get off clothes and skin and we highly recommend you use goggles, gloves and a lab coat. Thank you and have fun!
Procedure
This procedure was relatively simple due to our access to pre-made ferrofluid, if you do not have access to said compound there are tutorials for making your own or you can buy it. First we poured 20 ml of ferrofluid into a Petri dish making sure not to spill. We then attached a single neodymium magnet (1/2cm thick and 2cm in diameter), putting the flat end to the bottom of the dish, and used a very thin copper wire to measure the height (using the stain in the wire to measure with a ruler). Next, we turned the magnet on its side and again measured the height. After that, we added another magnet and repeated the previous process. We did this until we had four magnets on the bottom. After we finished that, we added 10 ml of ferrofluid to the dish, repeating all the processes with magnets. After we finished that we added another 10 ml to the dish and again repeated all the magnet tests.
Results
For the graphs below we are comparing the amount of fluid to the height and the number of magnets to the height. In both graphs, blue triangles are tests when the magnets were upright and red diamonds are when the magnets were sideways.
Amount of fluid in relation to the height of the fluid.
Number of magnets in relation to height.
Sideways
(cm)
Upright
Conclusions
For upright magnets, we found that adding magnets to the bottom of the dish did not affect the height of the ferrofluid. Though it comes as no surprise that four magnets made the highest tower, the thing that really affected the height was the amount of fluid. With four magnets and 4 ml of ferrofluid, we got a height of 1.5 cm. However with sideways magnets, the more magnets the shorter the fluid was. We found that using 2 magnets and 4 ml of fluid we got the highest result of 1.1 cm. More than 2 magnets causes the fluid to be stretched out and not go out as far. One magnet was not able to support all the fluid in the dish so it could not lift it up as far as two, even though it's more efficient. So if you ever play with ferrofluid, we recommend you use 4+ ml of fluid and 4+ magnets stacked on top of each other in a tower. If we were to extend this experiment, we would definitely add more fluid and more magnets to the conditions.
References
"How to Make Ferrofluids." Popular Science. Web. January 2011.
<http://www.popsci.com/diy/article/2009-09/making-ferrofluids-work-you>
<"Ferrofluid." Wikipedia. Web. January 2011.
<http://en.wikipedia.org/wiki/Ferrofluid>